For the last several years our laboratory has been concerned with the biochemical genetics of cell surface antigens and with the immunogenetics of bone marrow engraftment. In this proposal, I outline planned research: 1) to analyze the genetics of bone marrow transplantation in mice. 2) to carry out studies on the genetics of beta 2 microglobulin in man by utilizing a restriction- fragment polymorphism of the B2M gene 3) to produce additional Qa/TL monoclonal antibodies 4) to use biochemical methods to study the array of B2M-associated molecules and 5) to analyze the expression of transfected Qa/T1a region genes.